Detroit Radiator Corp. highlights its line of aftermarket replacement products at various industry events during the year via a unique tractor-trailer dubbed "Dr. Cool," a 1999 Kenworth W900 tractor powered by a 475-hp Cat diesel mated to a 13-speed manual transmission. With over one-million miles on its odometer, "Dr. Cool" is a hard-to-miss sight at trucking trade shows. (All photos courtesy of Detroit Raditator Corp., except as noted)